Echinacea, commonly known as Purple Coneflowers, are quintessential prairie plants. They are hardy, drought-tolerant, long-blooming, and are being cultivated in an ever-widening range of colors. It's hard to find a garden without at least one variety. Echinacea is a native North American genus with about ten species. Not all make great garden plants. Echinacea purpurea is by far the most popular. It has a more fibrous root system rather than the long taproot and woody crown found in other wilder species. As a result, it is more adaptable to garden conditions and more forgiving of dividing and transplanting.
The daisy-like flower is made up of several small flowers. The petals are sterile and lure insects toward the many fertile flowers in the central disk or cone. These flowers are rich in nectar and very popular with both bees and butterflies. Flowers were generally some shade of purple or lavender, with a dark center cone. Much hybridization has been taking place, and you can now find petal colors ranging from white to green through yellow, orange, and deep reds. The common name "coneflower" refers to how the petals angle backward, away from the center, forming a cone.
Growth starts with a clump of basal leaves, which eventually send up flower stems in mid-summer. The leaf shape depends on the variety. Many have oval leaves with a broad base, but some from dry, western areas often have narrow leaves.
Growing Conditions
Light: To get the most blooms and the sturdiest plants, plant them in a spot that gets at least 5 hours of full sun daily. They will tolerate partial shade, but plants may flop or strain to reach the sun.
Water: In seasons with average rainfall, additional watering is not necessary
Hardiness Zones: Coneflowers will grow well just about anywhere and are labeled USDA Hardiness Zones 3-9. You may want to give them a little winter protection their first year, but they are rugged and hardy once established.
Soil: Most Coneflowers grown in gardens prefer a neutral soil pH of about 6.5 to 7.0.
Fertilizer: Although they thrive best in soil high in organic matter, too much supplemental fertilizer can cause them to become leggy. The new hybrids need more TLC than the species.

Planting
If you don't want to start your own seeds, plenty of varieties are available for purchase as plants, especially through mail order. Plants can also be divided or grown from stem cuttings. Coneflowers can be planted in either spring or fall. Be sure to allow for good air circulation to prevent fungal diseases.
Coneflower hybrids tend to be sterile, but the species are relatively easy to grow from seed. If you'd like to save seed, wait until the cone has fully dried. It will be darker in color and stiff to the touch. The seeds are attached to the sharp spines. You don't need to separate them before storing or planting. You could plant the whole cone, and if you like, although you'll want to divide the many seedlings you'll wind up with. (If you grow multiple varieties and collect the seed yourself, you may well wind up with some interesting crosses.)
The seeds germinate best with some cold stratification. The easiest route would be to sow them outdoors in the fall, either in the ground or in winter sow in pots. If you are going to start seed indoors, simulate the chilling period by soaking the seeds in water and then placing the slightly damp seed in a sealed container in the refrigerator for 8 – 10 weeks. Then take them out and plant them as you usually would. They should germinate within 10 – 14 days.
Pests and Diseases
For the most part, Coneflowers have very few problems. I already mentioned giving them good air circulation so they aren't bothered by fungal diseases. If you should see mildew or spots on the leaves, simply cut them back and let them fill back in.
Aster yellows are a systemic plant disease that causes growth deformities in the flowers. It can affect hundreds of different flowers, not just those in the Aster Family. There is no known cure, and it is spread by a leafhopper, so affected plants should be removed and destroyed as soon as possible to protect nearby plants.
Grower's Tips
Coneflowers are often listed as drought tolerant, but they will do much better with regular water. I leave the plants standing through winter to feed the birds. Shearing them back in the spring will result in bushier plants that bloom longer into the season. Deadheading is the primary maintenance required with Coneflowers. They are prolific bloomers, and keeping them deadheaded will keep them in bloom all summer. Luckily each flower remains in bloom for several weeks. Flowers start blooming from the top of the stem. As the initial flower fades, more side shoots and buds will form along the stem. Keep the plants deadheaded, and you'll keep getting more flowers.
Source: about.com
Links
- Back to genus Echinacea
- Plantpedia: Browse flowering plants by Scientific Name, Common Name, Genus, Family, USDA Hardiness Zone, or Origin